Everyone knows and loves a secretary, if you don’t happen to have one of your own. The job has become quite commonplace and there is no mystique in the job. However, this was not always the case.
The etymology of the word, according to Wikipedia:
The term is derived from the Latin word secernere, “to distinguish” or “to set apart,” the passive participle (secretum) meaning “having been set apart,” with the eventual connotation of something private or confidential. A secretarius was a person, therefore, overseeing business confidentially, usually for a powerful individual (a king, pope, etc).
As you could have probably imagined, the word secret obviously stands out as the modern root of the word. Originally, only the rich and powerful had secretaries, and they were true confidants, and therefore, holders and keepers of secrets. Nowadays, the secretary is a common job, and really has lost its original usage except in cases like Secretary of State, Secretary of Defense, etc., which still pass along the impression that they are actually involved with a fair number of secrets.